The present paper examined the roles of educational planners in the promotion of in-service teachers' education for primary school teachers in Nigeria. Primary school education happens to be the foundation and bedrock for all other levels of education in any nation and therefore teachers at the primary school education must be thoroughly equipped, trained and qualified. The major means by which teachers can be equipped and trained is teachers' education. Teachers' education is in three phases- pre-service, induction and in-service teachers' education. In-service teachers education which is carried out via conferences, seminars, workshops, exhibitions, regular and correspondence courses at various teachers' institutions is aimed at improving the expertise, effectiveness and quality of serving teachers. It is also referred to as continuous education for teachers already in service. This is done to keep them updated and current in the teaching profession. Educational planners who are those that play a major role in the planning of all levels of education also play roles in in-service teachers' education. However, the roles they play and how they carry it out could determine the promotion of in- service teachers' education for primary school teachers in Nigeria. In this paper, conclusion and recommendations were given.